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View Full Version : Got a 4'x8' plotter for only a few bucks



Steve knight
05-04-2008, 4:11 AM
well I found another use for my cnc router. I bought a pen attachment and now I can draw with it.
so I can draw on the material to make sure everything is right draw out full size plans and parts templates, mark parts for assembly and draw pictures and such.
this goes along with the diamond drag tip I got so I can engrave things too.
here is a link to watch a couple of videos of it in action. it uses sharpie pens and had a sliding weighted tube so it can handle less then flat surfaces. so now I have a 4'x8' plotter for dirt cheap.
http://tinyurl.com/4sonwy
http://i154.photobucket.com/albums/s266/knighttoolworks/posting/drawingonthecnc3_resize.jpg
http://i154.photobucket.com/albums/s266/knighttoolworks/posting/drawingonthecnc4_resize.jpg

Keith Outten
05-04-2008, 8:31 AM
Steve,

I saw the link to this product on the ShopBot Forum a couple days ago and decided that I would order one for my shop. Looks like you beat me to it :)

I have been using my supervisor's HP inkjet plotter to plot large sign templates for installs. This looks like a less expensive alternative given the price of Sharpies, and they can be pruchased locally.

BTW I recently used the laser pointer you recommended to me a couple months ago on a very large sign to reorient the X origin. It did the trick and was far more accurate than I thought possible. Thanks again for the tip.

.

Steve knight
05-04-2008, 4:59 PM
it's a bit spendy for what it is but I debated on how much time it would take to hunt down the parts find a pen that would work and fit and said hell with it.
yes that laser has saved my butt I use it in my mill too.

Keith Outten
05-04-2008, 8:11 PM
It's my understanding that the pen attachment uses a weight to keep the pen in contact with the surface. I wonder why they didn't use a spring.

.

Steve knight
05-04-2008, 8:15 PM
yes just a weight. I think it may be hard to find a light enough spring. it would be more work to make it with a spring.

Richard Rumancik
05-07-2008, 10:34 AM
It's my understanding that the pen attachment uses a weight to keep the pen in contact with the surface. I wonder why they didn't use a spring.

Just a guess, but it seems to me that a "dead weight" on the pen would provide a constant downward force on the pen tip over a wide range of z-axis height. If you raise the axis by .050", the pen can drop down by .050" and the force on the tip of the pen should remain the same.

If you use a spring, and raise the axis .050, you have .050 less spring deflection. Therefore, since the force of a spring is proportional to deflection, it would reduce the downward force on the pen tip. At some point it just wouldn't have enough downward force to write.

So they probably did this to make it less sensitive to z-axis height.